320i to 325i what do i need

[cruizin4dirty1s]

i have an 89 320i and the head is gone just wondering what i will need to change it over do i need an ecu wiring loom and gearbox or does the gearbox fit since thier both m20's

[Cloggy Saint]

It's all plug & play mate. Gearbox will fit but the 2.0 ratios aren't ideally suited to the 2.5, likewise the diff' but it'll all be fine (about time this was made a sticky!)

[cruizin4dirty1s]

how will the different ratios affect it and i was thinkin of gettin a 325 lsd anyway would this make a difference do i have to change the ecu

[Cloggy Saint]

yeah, forgot to mention, you'll need to put a 2.5 chip in the original ecu. I'm not sure exactly about the ratios, but the gearing may be a bit short. Someone in the know will tell you sooner or later!

[cruizin4dirty1s]

where would i get the chip

[Speedtouch]

I can supply one, either standard or uprated - Mild or Wild.

[Cloggy Saint]

You could get a chip from Ant or speedtouch, both zone members.

[Cloggy Saint]

I can supply one, either standard or uprated - Mild or Wild.

Does you computer light up every time someone posts the word, chip?

[cruizin4dirty1s]

how much with wild and what sort of hp would wild give

[Speedtouch]

Wild is £30 posted and provides up to 192bhp when used in conjunction with 268/268 cam, six-branch and BBTB, around +10bhp on a standard engine.

[320ise]

from what i have read in the past the 320i box has the same ratios as a 325i sport (close ratio box) but the 320i unit is not as strong as the sport one (but do the same job in practice) with a 3.91 or 3.64 should drive power wise the same as a sport, i would myself use the 3.64lsd as i find it bit leggyer than the 3.91. not 100% sure if this is all correct i am sure some one will correct me soon if am wrong!

[leeparkes]

Im sure you need the b25 air flow meter too!
320 exhaust will be slightly different in diameter causing a bit of a restriction,
other than that its plug and play assuming the lump comes with inlet manifold & TB!

[BigBavarian]

If you end up changing the rear diff there is also the option to upgrade the rear brakes from drums to discs, unless your car already has them or is a tourer or cab.

[scottidog]

i have an 89 320i and the head is gone just wondering what i will need to change it over do i need an ecu wiring loom and gearbox or does the gearbox fit since thier both m20's

Hi mate. I bought a 320i with a 325 engine in it, it originally belonged to fingerman so it might help if you asked him, this is what mines had fitted to that i think may have been related to the swap, i have the recepts

front timing case
distributer and rotor
ht leads
facelift M20 loom and ecu
M20B25 inlet manifold
M20B25 injectors
M20B25 Throttle body
Idle control valve
Inlet maifold gasket set
Inlet boot
Air flow meter
Crank pulley & crank position sensor
Coolant hoses, stat housing

It says they have swapped the ecu and loom for Motronic If that helps.
Sorry if some of this isnt nessesary but thats whats been done to mine since the engine was fitted by the same people who did the work above.

[scottidog]

Sorry i forgot to mention mine still has the 2.0 gearbox and diff which feel fine, if anything it runs out of breath too early...... I also still have the 320 single exhaust pipe fitted center to rear which i really hate as i know for a fact its strangling the crap out of it!!!! And doesnt sound as good either.

[daimlerman]

My 2.7 is built from a 320i 4 door,still using the 320 gearbox and clutch,no issues in more than 30,000 miles. I did swap the 4.1 diff for a 3.64,though.